Electrically heated sterilizing and cooling apparatus adapted to be used as an ice box



Oct. 1, 1935. M, ABRAHAM 2,015,775

ELECTRICALLY HEATED STERILIZING AND COOLING APPARATUS ADAPTED To BE USEDAs AN ICE Box Filed NOV. 7, 1954 @If/507, //f/f/ fg. 3 la Patented Oct.1, 1.935

PATENT OFFICE ELECTRICALLY HEATED STERIIIZING'-AN`D COOLING APPARATUSADAPTED TO BE USED AS AN ICE BOX Manfred Abraham, Berlin, GermanyApplication November 7, 1934', Serial No. 751,909

In Germany October 5, 1933 6 Claims. (Cl. 219.-35)

This invention relates to a sterilizing apparatus in which thesterilization is effected by the action of heated air on the goods to besterilized, for example medical and surgical instruments, bandages,rubber articles and other goods.

According to the invention the sterilization is carried out with the aidof a hermetically closable container provided with thermie externalinsulation and containing an electric heating element for supplying thenecessary heat. As the sterilizing chamber is hermetically closed onlythe heated air enclosed therein acts on-the goods to be sterilized,which are placed in the chamber, the maximum temperature of the airbeing automatically regulated. A detrimental effect upon the goods to besterilized can consequently not take place as in all other methods ofsterilizing.

The limitation to a maximum internal tempera- I ture according to theinvention can be attained in that the capacity of the electric heatingelement and its dimensioning is in a certain relation tothe heataccumulating capacity or to the heat conductivity and to the thicknessof the layer of insulation employed, and any excess of heat is led on tothe outer side through the insulation layer. If the apparatus is to beemployed for different sterilizing temperatures, it is provided with anautomatically operating thermo-regulator by which the current isswitched off when a certain internal temperature is reached.

For the purpose of increasing the heating effect and its uniformdistribution over the whole of the interior of the container, thiscontainer is preferably provided with a polished metal lining, which byreflection of the heat rays prevents any undesirable absorption of heatby the container wall, especially by its insulation.

The electric source of heat is advantageously iixed on the inner surfaceof oneor more side walls of the sterilizing chamber, preferably oppositethe door. The heat raysare then directed towards the `coldest portion ofthe sterilizing chamber which is evidently near the door.

Both the sterilizing apparatus and also the source of heat may befoldably mounted in order that the source of heat may be employed invertical or horizontal position. The device for actuating the same maybe coupled-with another device Which during the folding over of thesource of heat positively changes its electric resistance andconsequently its heating e'iciency. The container is automaticallyadjusted to diierent working temperatures in each of its two positionsof use.

Recesses may be provided in the sterilizing chamber for accommodatingthe electric heating element and receptacles for cooling media and thelike. The apparatus, if cooling media, such as solldied carbon dioxide,are accommodated therein, can be used as an ice box, when the source ofh eat is switched out.

In order to accelerate the cooling of the container walls after the heattreatment has been terminated, when it is desired to change over the"apparatus for cooling purposes, a cooling means,

such as a water coil fed from any suitable source, l0 is preferablybuilt into the insulating layer.

It is important for the sterilization, that all possibility of oxidationis eliminated, for example in the case of metal articles to besterilized. This is attained in a vperfect manner according to the l5invention in that the oxygen of the imprisoned air is used up by theresistance wire of the electric source of heat. For this purpose thesource of heat is so arranged that it acts directly on the air. Theresistance wires are therefore situated in the 20 sterilizing chamberand only protected against damage and contact by a netting. The heatingeffect is also considerably increased by this arrangement of theresistance wires.

Hollow spaces or air spaces are preferably provided in the insulatinglayer for preventing any effect of the external temperature.

The sterilizingy apparatus is, according to the invention, tted with aseparate temperature regulator by means of Which any alteration of thedesired temperature is prevented in, the sterilizing chamber. Thistemperature regulator consists of an element expandingunder heat andwhich at a certain temperature acts on a valve or the like so that coldair can iloW into the chamber and 35 the excess of heat is dischargedfrom the chamber. By inserting differently regulatable elementsexpanding under heat, it is possible to regulate to any desired maximumtemperature.

The door of the apparatus is vprovided with 40 closing devices effectinghermetic closure.

The apparatus may also be employed as cooking apparatus besides forsterilization and cooling purposes.

Two embodiments of the invention are illus- 45 trated in theaccompanying drawing, in which:-

Fig. 1 shows an apparatus in side elevation partly in section.

Fig. 2 is atop plan and part sectional view of Fig. 1.

Fig. 3 shows a modiiied form of construction in longitudinal section.

The outer casing l 'of the lapparatus encloses an insulating layer 2,the exposed surface of which is lined with metal foil 3. An electricheating coil 5 is accommodated in a recess I in the wall of thecontainer and separated from the interior of the container by a wirenetting l. Hinge plates 8 are slidably located between guide ribs I onthe side wall and held in position by means of pins I0 engaging in slots9 in the hinge plates 8. The container door i2 is carried on the otherend of these hinge plates I by means of hinges Il. This door I2 alsoconsists of an outer wall I, an insulating layer 2 and a polishedmetallic lining 3. r:'he door I2 is provided with packings i I3hermetically fitting in the rebate Il on the edge of the open side ofthe container when the door is closed. Turn-buckles i5 are foldablymounted one on each side wall of the container and when the door isclosed, they engage in corresponding forks I8 projecting laterally fromthe door. By tightening the wing nuts of the turnbuckles, the hingeplates I slide in their guides I and the door is tightly pressed intothe rebate. The current leads, switches and the like and also thecontrol thermometer I`I are of usual construction.

According to Fig. 3 air chambers 25 are provided directly in theinsulating layer 2 or in the wall I or 3. The door i2 can be swungdownwards about hinges Il. All the edges of the door are bevelled. Whenbeing closed, the door, which has packings i3 on its edges, hermeticallyfits in the rebate il provided with similar bevelled surfaces. A screwII projects from the rebate I4 and for locking the door engages a screwnut I9, the nut being actuated from the outer side of the door by meansof a handle 2U rotatably mounted therein. One or several such closingdevices I8, I9, 20 may be provided at one or several points of theapparatus.

For the continual automatic regulation of the desired temperature in thesterilizing chamber the following arrangement is provided according tothe invention:-

A temperature regulator consisting of an element 2| expansible underheat is fitted either in any of the walls of the casing or, as shown inFig. 3 in the door. This element is iltted in a guide 22 made ofsuitable material mounted in the door and xed at 2l on the side adjacentthe interior of the sterilizing chamber. The air imprisoned in thesterilizing chamber can thus ilow directly against this inner end of theelement 2l.

On the freeend of the element 2| a valve 24 is mounted which, when theelement 2| expands,

opens slightly so that cold yair can flow into and.

the excess heat can be discharged from the chamber. The valve 24 againcloses when the element 2i contracts. This procedure recurscontinuallyand maintains a constant maximum tempera ture in the sterilizing chamberindependently oi the external temperature and without switching in andout of the electric heating.

The place at which the expansible element is tted and its constructionmay be chosen to suit the actual requirements.

'I'he door may be provided with a known contact device which interruptsthe current supply when the door is opened.

I claim:-

1. A sterilizingand cooking apparatus comprising in combination an outercasing adapted to be set up selectively on one of two adjacent sides, adoor on one end of said casing, an insulating layer on the inner side ofthe walls of said casing and said door, said layer having a recessopposite said door, a metal foil lining said insulating layer to 4form aheating chamber and having an aperture registering with the recess insaid insulating layer, an electric heating coil in the recesses in saidinsulating layer so that the heat rays are always directed towards thecoolest portion of said chamber, and a wire netting over the aperture insaid metal foil lining separating said I electric heating coil from saidheating chamber.

2. In a sterilizing and cooking apparatus as specified in claim l,hinges secured to one edge of the door and eac'n having a. slottedplate, pins on said casing one engaging in the slot of each of l saidplates and adapted to hold said hinge plates in position on said casing,ribs on the outer side of said casing adapted to guide said hingeplates, forks on the outer side of said door projecting beyond twoopposite edges thereof, and turnbuckles one on two opposite walls ofsaid casing each turnbuckle adapted to engage one of said forks to pullsaid door tightly against said casing.

3. In a sterilizing and cooking apparatus as specified in claim 1,hinges secured to one edge 5 of the door and each having a slottedplate, pins on said casing one engaging in the slot of each of saidplates and adapted to hold said hinge plates in position on said casing,ribs on the outer side of said casing adapted to guide said 1 hingeplates, forks on the outer side of said door projecting beyond twoopposite edges thereof, turnbuckles one on two opposite walls of saidcasing each turnbuckle adapted to engage one of said forks to pull saiddoor tightly against said 3 casing, a rebate formed on the walls of saidcasing adjacent said door, and packings on the inner side of said dooradapted, when the door is closed, to engage vsaid rebate and formtherewith a hermetic closure. 4

4. A sterilizing and cooking apparatus as specified in claim 1 in whichthe metal foil lining the inner side of the door is polished to split upand reflect the heat rays impinging thereon from the heating coil. 4

5. In a sterilizing and cooking apparatus as specified in claim 1, thewalls of said casing bevelled at the end adjacent said door, and saiddoor bevelled towards each edge to correspond with the bevelled portionof said casing walls, a re- 5 bate formed on the inner end of. thebevelled portion of said casing walls, packing on the inner wall of saiddoor adapted to bear against said rebate when the door is closed, saiddoor having a hole near one of its edges, a screw forwardly 5'projecting from the rebate on the wall opposite said hinges and adaptedto extend through said hole when the door is closed, and a screw nut insaid hole adapted to engage said screw to press said door tightlyagainst said casing, and a han- 6i die on said nut adapted to rotate thesame.

8. In a cooking and sterilizing apparatus as specified in claim l, atemperature regulator comprising'an element expansible under heatmounted in said door, a guide carrying said element 6 and fixed to theinner side thereof, and a valve on the outer end of said element adaptedwhen the temperature in said chamber reaches a pre determined maximum toopen under the influence of the expanding element to ventilate saidcham- 7( ber.

MANFRED ABRAHAM.

